1. Field of Invention
The leak detection system for the detection and monitoring of pressurized refrigerant systems, primarily walk-in refrigeration units in stores or storage facilities, monitors and controls the refrigeration system which store and preserve perishables. The system includes a gas refrigerant detector and a monitor and relay system to alert the store personnel and remote monitoring stations that a problem exists by detecting the presence of gas outside the system within the refrigeration units, assessing the magnitude of the problem, and providing an emergency shutoff means to close and contain the refrigeration system contents in the event a substantial refrigeration leak is detected, closing the system until system repairs are made and the system is manually reset.
2. Description of Prior Art
In the industry, there are numerous monitoring systems which detect a variety of chemicals and environmental contaminants, as well as environmental conditions. Different sensors are presented to detect gas, vapor airborne particles or liquids. However, no specific detection systems to monitor air quality in refrigeration units or detect refrigeration leakage has been presented until the disclosure of this invention, which is adapted to monitor one or more refrigeration units per site and convey information to site personnel as well as a remote monitoring location.
The following United States patents were discovered and are disclosed within this application for utility patent. Three simple gas detection devices are identified in U.S. Pat. No. 4,958,503 to Thompson, which uses a liquid reservoir to sense gas bubbles, U.S. Pat. No. 5,846,833 to Clough, to withdraw gas from a closed system to test non-hydrocarbon refrigerants for the presence of hydrocarbons through pressure measurement, and U.S. Pat. No. 5,419,177 to Pastorello, to measure the presence of contaminants in a refrigerated gas under pressure.
In a U.S. Statutory Invention Registration No. H1676 to Marshall, a system for the monitoring of combustible liquid gas in service stations is disclosed which monitors fuel spillage and area and environment contamination using non-mechanical fluid sensors in communication with a central processor, which also may involve the use of fail safe self diagnostic devices, differentiating sensors, specifically Hall Effect sensors. The system distinguishes the source, nature and severity of a leak or spill of fuel and other fluids, provides a local or remote signal and compiles historical and analytical data relevant to the recorded events, integrating these functions with other function of recording of service station operations.
U.S. Pat. No. 5,351,037 to Martell, discloses a refrigerant gas leak detector that operates using a high voltage current across a pair of electrodes so that a corona current is generated through the electrodes, and also contains a gas sensor circuit that detects changes in the concentration of the refrigerated gas present in the vicinity of the sensing tip based upon the magnitude of voltage across the tip. This patent discloses the method for using the device and also the device which includes a sensing tip having a pair of electrodes, a generating means for the production of the voltage across the electrodes, a controlling means on the generating means, and a detection means coupled to one of the electrodes for detecting the change in the refrigerated gas concentration. There is also a signal differentiating aspect in the invention with a comparative first base signal and a second instantaneous signal, which could be applied to an alert means as to differential measurement of gas levels.
However, none of the above devices, either alone or in combination, provide the elements or function of the current system, nor do they combine to serve the stated use or function of the gas leak detection system.
In many large stores and storage facilities, there are often several walk-in refrigerated units containing perishable items, which contain multiple refrigeration closed pressure systems. Monitoring these systems requires technology to sense the presence of refrigerated gas leaks in the system prior to a major problem, which could result in complete loss of all refrigerated gas within the system, damage to the refrigeration system by continued operation without pressure, gas or gas lubricant, and also the loss of the contents within the refrigeration unit, including food, medicine and other products and supplies requiring refrigeration, as well as danger to personnel inside the confined space of the walk-in refrigeration unit. In many instances, there is not sufficient alternative storage facilities in the vicinity, and those stored items are simply lost during system failure. This loss of product, loss of refrigerant without system shutdown, and damage to the system is not only expensive, but it could also be detrimental to personnel and the environment.
The current gas leak detection system provides a graduated monitoring system that senses different set levels of refrigerated gas within the walk-in refrigeration unit, relays signals and warning of such leak detection and automatically causes system shutdown and capture of remaining refrigerated gas within the system, preventing damage to the system, minimizing loss of refrigerated gas and also alerting local and remote monitoring station of system problems so that immediate arrangements for repair, evacuation of personnel and preservation of contents can be instituted to minimize loss of product.
The primary objective of the gas leak detection system are to provide a local and remote monitoring system in walk-in refrigeration units to monitor and detect refrigerant leaks, relay information as to status and leak detection in the air within one or more walk-in refrigeration unit. A second objective of the invention is to provide a system which, after having sensed a quantity of refrigerant in the walk-in refrigeration unit, causes the system to shut down and retain the remaining gas refrigerant within the system. A third objective is to provide a several stage warning system to alert the store monitoring personnel of a system failure with sufficient time to evacuate the personnel and correct the problem before a major system failure occurs.